dev.bce.X.com_no_buffers increasing and packet loss
davidch at broadcom.com
Fri Mar 12 23:58:48 UTC 2010
> Pyun YongHyeon wrote:
> > On Wed, Mar 10, 2010 at 02:45:47PM -0800, David Christensen wrote:
> > > The bce(4) hardware supports a linked list of pages for RX buffer
> > > descriptors. The stock build supports 2 pages (RX_PAGES) with a
> > > total of 511 BD's per page. The hardware can support a
> maximum of
> > > 64K BD's but that would be an unnecessarily large amount of mbufs
> > > for an infrequent problem.
> I think that depends on how you define infrequent. Our use
> case is a largish core router. It's highly likely that we'll
> see this again and again in various packet storms on our network.
Are the packet storms always always from the same host or do they come
from multiple hosts? The hardware supports RSS which can spread the
network load across multiple receive queues and multiple CPU cores, but
only when the traffic is spread across several hosts. (The current
bce(4) driver doesn't include support for RSS.) If a storm of
small frames comes from a single host then almost all adapters will be
challenged to handle the flow.
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